Seal for closures



July 23 1935 J. R. ALLAN 2,008,741

SEAL FOR CLOSURES Filed Feb. 5, 1932 2 Sheets-Sheet 1onHuHHHHHHInIlHHHHnHHHUJlHhha, www .\\\\|.h"..PlhlnluniluvnhhvuHMHJJJrw. n Il ..\||l|||\|||\l!.t\|||u||i @9021 oooo 6 0@ L d# QW.; wm ww @miI v I O O O n u July 23, 1935.

J. R. ALLAN SEAL FOR CLOSURES med Feb. s, 1932 2 Sheets-Sheet 2 l MN.

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Patented July 23, 1935 UNITED STATES PATENT GFFICE 2 Claims.

This invention relates to a seal for closures.

More particularly, it relates to an air seal particularly designed foruse with the doors, turntables and other closures of sand blast roomsand equipment.

The principal object of the invention is to construct a seal forclosures which is substantially air, dust anddirt tight and which isdependable and serviceable in operation.

Another object is to provide an air and dust tight seal which isactuated or placed inoperative relation after a closure is in place inits supporting frame and which is removed from engagement before theclosure is removed.

Another important object of the invention is to provide a control meanswhich permits the actuation of the sealing means only when the closuresare in closed position.

Another object is to provide in a room or compartment particularlydesigned for sand blasting, a control for the sand blast air of such anature that the sand blast can be operated only when the doors and otherclosures, which are provided with the seals embodying the invention, arein closed position with therseals extended into operative position.

The objects of the invention are accomplishedV by the provision ofpneumatic tubes secured to the closure or to the frame which surroundsthe closure. The tubes may be tted in suitably formed recesses. Thetubes are extensible through the open side of the recesses whereby Wheninflated they engage the adjacent wall and form a substantially airtight seal. The air pressure for inflating the tubes is supplied fromthe same air line which is utilized for supplying air for sand blastingequipment. Valves are positioned inthe main air supply line ahead of thebranches running to the pneumatic tubes and to the sand blast equipment.These valves are positioned and constructed to be operated by closingthe doors and or turntables of the sand blast chamber whereby air cannotbe .supplied until the doors and or turntables are closed. A 3-Way valveis positioned in the main line between thek safety valves operated bythe closing of the doors and the branches leading to the pneumatic tubesand to the sand blast equipment. This valve is manually operable to cutoff the main air supply and tobleed the air from the pneumatic seals,whereby the doors may be opened. It is then impossible, even byactuation of the S-way valve, tovsupply air to either the pneumatictubes or the sand blast equipment until the doors are again closed.

In the drawings:

Figure 1 shows a wall of a sand blast room or chamber containingl anopening around which a frame work is constructed;

Figure 2 isa sectional View taken on the line 2-2 of Figure 1, showingin addition, in a somewhat diagrammatic manner, the air supply anddistribution means for operating the pneumatic seals and the sand blastequipment to be utilized;

Figure 3 is an enlarged sectional View, showing one means for mountingthe pneumatic door seals embodying the inventiornthe dotted positionshowing the tube inflated in its sealing position; and Y Figure 4 is anenlarged sectional View showing a modification of the means for mountinga pneumatic seal of the invention.

Doors I0, carried on hinges II attached to the framework of the mainwall, are swingable to open and close the opening therein. These doorsmay be of any conventional construction, usually being built up of metalplates properly reinforced with angle bars.

As shown in Figure 3, angle bars I2 secured around the plates formingthe door, are spaced from the outer edges thereof to provide formounting the pneumatic tube. A metallic bar I3 substantially circular incross section, is positioned` in the recess formed by the angle bar I2,the main plate of the door I il, and an angle bar i4 which is a part ofthe frame surrounding the doors. The member I3 is cut away forsubstantially 90 of its circumference on the side adjacent the bar I4. Aheavy Walled rubber tube I5 is mounted Within the member I3. Said tube,in uninflated condition, has an external diameter substantially the sameas the internal diameter of the member I3. The walls of the tube aresumciently thick to hold the tube in substantially circular positionwhen it is vnot inilated and when the interior of the tube is incommunication with atmospheric pressure. It will be noted that asubstantial clearance is provided between the angle bar I4 and theadjacent wall of the tube I5 when the tube is not inflated. An inflationtube I6 extends through the tube I5, through the member I3, and throughthe angle bar I2. The modification shown in Figure 4 is substantiallythe same as that shown in Figure 3. The angle bar I 2 has an extensionIl which is substantially parallel to the main plate of the door it). Ashaped, Wooden member I8 is iitted into the recess formed bythe door I0,the angle bar I2', and the extension I1. Said member has a bore formedtherein substantially circular in cross section, being open on the sideadjacent the frame `bar I4. The tube I9, fitted in the member IS, is ofthe same construction as the tube I5, previously described.- Aninflation tube I6 extends through the bar I2 and the member I8, into thetube I9 for inflation thereof.

As shown in Figure 2, the doors, as illustrated,

are so constructed that they come together at theV center. Latch bars20, pivoted on one door at vertically spaced positions, are connected together by an operating bar 2 I. As shown in Figure 2, one of the latchbars 2i! is rigidly secured to a pin 22, which extends through the door.An operating arm 23 is rigidly secured to the pin 22 inside the door,whereby the latch bars may be lifted to open the doors from eitherwithin or without the sand blast chamber. The latch bars 20 extend fromthe door on which they are pivoted, over the edge of the other door.Latches 2Q are provided on said second door with which the bars 2G areengaged when the member 2l is opH era-ted to lock the doors.

A main air supply line 25, as diagrammatically shown in Figure 2,extends into the sand blast room for supplying air under pressure, bothfor operating the pneumatic seais and for operating sand blastequipment. Tivo exactly similar valves 26 are positioned in series intheair supply line 25. Each valve consists oi the main outer casing anda piston 2l mounted orreciprocation therein. The piston has a connectingrod 23 which extends through the main valve casing and is provided withan engaging head 29, positioned where it will be engaged by closingmovement of the door behind which it is positioned. A spring 30, seatedagainst the valve casing and'against a stop place on the connecting rod23, resiliently urges the connecting rod into an extended position. Thepiston on said rod is so positioned that When the connecting rod is inextended position the piston will close thevalve against the flow ofair. A S-Way valve 3l is positioned in the main air supply line 25beyond the valves 2S. This valve may be of any conventionalconstruction, having three series of huid communication as illustratedby the pipes 32, 33 and t4. The valve is so constructed and operatedthat air flow may be provided for from the pipe 32 to the pipe 33 orfrom the pipe 33 to the pipe 34. Beyond the bypass valve 3l a B-wayconnection 36 is provided by which the air pressure from the pipe 33 is'communicated at all times to a conduit 37 and a conduit 38. The conduitSi is connected to a valve 39, which is in turn connected to a conduit4U, which delivers to the sand blast equipment to be utilized. Theconduit 38 is connected by a 3-way connecting member il to conduits 52and 43. These conduits, as well as the other conduits illustrated, areflexible, that is, they may be constructed of conventional high pressurerubber tubing. The conduits /iZ and i3 are connected to the inflationtubes I6.

In operating the seals, as described above, and the air supply systemassociated. therewith, air is supplied to the line 25 under a suitableregulated pressure. Assuming that the doors are in open position andthat all arrangements have been made within the sand blast chamber forperforming blasting Work, the operator enters the compartment, closesthe doors il? and locks them in closed position by operation of thecontrol handle 23. W hen the doors swing into closed position theirinner sides engage the connecting rods 23 and open the valves 26 to theflow of air therethrough. The 3-way valve 3l is then operated to permitair fiow from the pipe 32 to the pipe 33. Air pressure is thentransmitted through the conduit 38 and the conduits l2 and d3 to thepneumatic tubes l5. Said tubes upon inilation are extended to theconduit line position shown in Figures 3 and 4, whereby a substantiallyair and dust tight air seal having an appreciable contact area, isobtained. The operator may then by acrtuation of the valve 39, supplyair to his sand blast equipment.

When the work within the sand blast chamber has been nished, theoperator may either turn oi the valve 3s first or he may merely actuatethe `eway valve 3i. When the valve 3i is operated to cut ofi the supplyof air pressure and to put the pipe 3S in communication with the blowoff pipe 353, air pressure is relieved from the Vpneumatic tubes i5, andthey take their cylindrical shape in spaced position away from thecontacting Walls. The doors may then be unlatched and opened.

It will be noted that in the particular embodiment ofthe inventionillustrated, the tivo adjacent tubes at the center where the two doorscome together, engage each other upon inflation. This is a particularfeature of the construction, as the same principle may be utilizedwherever a plurality of closure members are utilized or any reason. Asshown in Figure l, the corners of the doors are rounded to permit theuse oi relatively long radius curves on theY elbows necessary in thepneumatic tubes. It has been found that the long radius curves at thecorners permit a construction by which a better it may be obtained. Theonly requirement is that the frame around the doors or closure members,have an abutting surface adjacent the` pneumatic tubes of the samegeneral shape and in slightly spaced relation thereto to prevent anybinding or rubbing action when the closures are placed into or removedfrom position.

lt is to be understood that applicanthas shown and described onlycertain preferred embodiments of his improved pneumatic seal and that heclaims as his invention all modications falling within the scope oi theappended claims.

What is claimed is:

1. A pneumatic seal for sand blast rooms and equipment comprising, incombination With a wall having an opening formed therein and a framesurrounding said opening, a door hinged to said frame and swingable to aclosed position against the frame, thereby substantially closing saidopening, an endless resilient tube surrounding the door and securedthereto, said tube being positioned between a portion of the door and aportion of the frame, means to inflate said tube whereby it is extendedinto contact with the frame, thereby forming a substantially air anddust tight seal, means operative to permit the inflation of said tubeonly whentheA door is in closed position, and further means operativelyinterlocked with the door to operate the sand blast equipment only whenair is supplied to the sealing tube.

2. A pneumatic seal for sand blast rooms and equipment comprising, incombination with a wall having an opening formed therein and a framesurrounding said opening, a door hinged to said frame and swingable to aclosed position against the frame, thereby substantially closing saidopening, an endless resilient tube surrounding the door and securedthereto, said tube being positioned between a portion of the door and aportion of the frame and being tree from contact with the frame duringswinging of the door, means to inflate said tube whereby it is extendedinto contact with the frame, thereby forming a substantially air anddust tight seal, means operative to permit the inflation of said tubeonly when the door is in closed position, and further means operativelyinterloclred with the door to operate the sand blast equipment only whenair is supplied to the sealing tube.

JAMES R. ALLAN.

